Calling a functions return value as a variable - Soundcloud API

Question

I'm trying to debug in Chrome's console and have created this small function for testing.

var hello = function(){
  var text = "Hello World";
  return text;
};

It works as I want it to, and when I call the function hello(); It returns the string "Hello World".

Now I'm not getting the same with this function using the Soundcloud API resolve endpoint.

 var idGetter = function(){ 
    SC.get('/resolve', { url: userURL }, function(user) {
      SC.get('/users/', function() {
        return (user.id);
      });
    });
  };

When I replace the return with console.log I get the value I'm looking for in the console so I know it's getting the data out, but when I use return I'm not able to call a value as I did in the "Hello World" function above.

Can add more code if it helps.

same thing if you remove the brackets? ```return user.id;```@jermainecraig — Paul Fitzgerald, May 06 '15 at 23:40
This is normal js your function is returning before the get because it is asych — Jackie, May 06 '15 at 23:41
https://github.com/kriskowal/q might help you too if you returned a promise then waited for it you would be fine. — Jackie, May 06 '15 at 23:43

Jackie · Accepted Answer · 2015-05-07T01:36:39.773

This is typical Javascript behavior what is going on here is that the return is happening here....

var idGetter = function(){ 
 SC.get('/resolve', { url: userURL }, function(user) {
  SC.get('/users/', function() {
    return (user.id);
    // not here
  });
 });
 // Return happens here 
};

That is why the return is probably undefined. There are 2 ways people normally handle this, callback or promises.

1.) Callbacks

var idGetter = function(callback){ 
 SC.get('/resolve', { url: userURL }, function(user) {
  SC.get('/users/', function() {
    callback(user.id);
  });
 });
};
idGetter(function(id){
  return id;
})

2.) Promises

This is probably the route to take, if you are using a framework it may already include this, however, if not just include this library.

var idGetter = function(){
   var deferred = Q.defer();
   SC.get('/resolve', { url: userURL }, function(user) {
     SC.get('/users/', function() {
       deferred.resolve(user.id);
     });
   });
   return deferred.promise;
}

There are other options for handling this scenario but these are the 2 most common.

Update:

The other answer works with something like this but will not work on most mobile browsers yet (hopefully soon)

Think i'll go with Promises, only i'm getting this error "deferred.promise is not a function". Added the library with a script tag, and replaced with your code. Doing some reading into it, and it seems it's already in jQuery? Would this mean I don't have to add the library? — jermainecraig, May 07 '15 at 00:15
Sorry should be defer.promise not defer.promise() Some frameworks include promises, I would use this one https://api.jquery.com/deferred.promise/. The ECMA promise has a bit of a different syntax — Jackie, May 07 '15 at 01:36

Calling a functions return value as a variable - Soundcloud API

1 Answers1